Grinding attachment



1955 w. o. SHOBROOK GRINDING ATTACHMENT Filed Jan. 20, 1954 INVENTOR. W0. 36 0 Z roo in ATTORNEY United States Patent M GRINDING ATTACHMENT William 0. Shobrook, Livingston, Ky.

Application January 20, 1954, Serial No. 405,118

2 Claims. (CI. 51-92) This invention relates to a novel attachment for use with a grinding wheel for effectively supporting a blade or the like with an edge thereof properly disposed to be engaged and sharpened by the grinding wheel and by means of which the part to be sharpened may be readily moved transversely of the grinding wheel for effecting a sharpening of the edge from end-to-end thereof without changing the angle of the edge being sharpened relatively to the grinding wheel and without movement of the part being sharpened either toward or away from the grinding wheel.

More particularly, it is an aim of the present invention to provide a support for an element to be sharpened by a grinding wheel wherein no angular adjustment of the element relatively to the grinding wheel is required and which is so constructed that the element will always be disposed at a correct angle relatively to the periphery of the Wheel when supported by the attachment and with the attachment parts assembled.

Still another object of the invention is to provide an attachment including a workpiece carrying part in which the element to be sharpened is secured and which part is supported solely by gravity in an applied position to position the element to be sharpened at a correct angle relatively to the grinding wheel and which workpiece supporting part with the workpiece applied thereto may be quickly and easily applied to or removed from the remainder of the attachment.

Still a further object of the invention is to provide an attachment of the aforedescribed character of extremely simple construction capable of being economically manufactured and sold and which will be extremely efiicient and durable in use and by means of which numerous tool bits or blade elements may be accurately and easily sharpened.

Various other objects and advantages of the invention will hereinafter become more fully apparent from the following description of the drawing, illustrating a presently preferred embodiment thereof, and wherein:

Figure 1 is an enlarged cross sectional view of the attachment shown in an applied position, taken substantially along a plane as indicated by the line 11 of Figure 2, and showing a part of a grinding wheel in side elevation;

Figure 2 is a top plan view, partly broken away and on a reduced scale thereof, and

Figure 3 is a cross sectional view taken substantially along a plane as indicated by the line 33 of Figure 1, and on a reduced scale.

Referring more specifically to the drawing, the grinding attachment in its entirety and comprising the invention is designated generally 5 and includes an elongated mounting plate 6, an elongated guide member, designated generally 7, and a workpiece supporting carriage, designated generally 8.

For the purpose of illustrating a preferred application and use of the attachment 5, a portion of a rotary driven grinding wheel 9 has been illustrated in Figures 1 and 2,720,059 Patented Oct. 11, 1955 2 together with a part of the grinding wheel shield 10 which is provided with an outwardly extending lip or flange 11 at one end thereof. The lip or flange 11 has an upper surface 12 which is disposed substantially perpendicular to the adjacent portion of the periphery 13 of the grinding wheel 9, for a purpose which will hereinafter become apparent. The shield 10 including the flange 11 may constitute a part of a supporting structure or stand, not shown, for said grinding wheel.

A headed screw 14 is turnably disposed and countersunk in an opening 15 of the mounting plate 6 and threaded engages a tapped or threaded opening 16 of the flange 11 for detachably clamping the mounting plate 6 against the upper flange surface 12 so that a front edge 17 of the plate 6 will be spaced from and disposed substantially parallel to the adjacent portion of the wheel periphery 13 and so that side edges 18 of said plate 6 will be disposed at substantially right angles to said adjacent portion of the wheel periphery. A rear portion of the plate 6 projects outwardly from the outer edge 19 of the flange 11 and said rear plate portion is provided with a depending ear 20 which is spaced outwardly a substantial distance from the outer flange edge 19 and which is provided with a threaded opening 21 which is disposed parallel to the side edges 18.

The guide 7 comprises a relatively thick rigid elongated bar having an elongated transversely extending slot 22 intermediate of its ends through which :a headed bolt 23 looselyextends. The shank end of the bolt 23 threadedly engages a threaded opening 24 formed in the plate 6 behind and preferably in alignment with the opening 15. The head of the bolt 23 is disposed on the upper side of the guide 7 and has a sufficiently loose fitting engagement therewith to permit the guide 7 to slide on the plate 6 toward and away from the grinding wheel 9. The guide 7 near its outer or rear edge and in trans verse alignment with the slot 22, is provided with a depending apertured lug 25, the aperture or bore 26 of which is disposed in alignment with the threaded bore 21. An unthreaded portion of a headed bolt 27 is journalled in the bore 26 and the threaded shank end of said bolt extends through and threadedly engages the bore 21. The bolt 27 is prevented from sliding relatively to the lug 25 by the head thereof which engages against the outer side of said lug and by a collar 28 which is secured to the bolt shank and engages against the inner side of the lug 25.

The elongated bar forming the guide 7 has a longitudinally extending inner or front edge which is turned upwardly to form a front wall 29 which is disposed substantially perpendicular to the plate 6 and substantially parallel to the front edge 17 thereof. Said front wall 29 has a top surface 30 forming a track or rail and an inner surface 31, the upper portion of which forms a secondary track or rail. The other longitudinal edge of the bar forming the guide 7 is turned upwardly and inwardly to provide an upwardly and inwardly or forwardly inclined rear wall 32 the inner side 33 of which combines with the adjacent portion of the upper surface of the intermediate part of the bar to form a groove of substantially V-shape in cross section, as seen in Figure 1, the other surface 34 of which is formed by a part of said intermediate bar portion.

The work supporting carriage 8 comprises a block or strip provided with a substantially flat top surface 35 which extends from a forward end 36 of the carriage to a point spaced from the rear end of the carriage. Rearwardly of the top surface 35, the block or strip is substantially reduced in thickness and has a rear end 37 which is downwardly offset from the plane of the surface 35 and which is of substantially V-shape cross section to snugly fit between the surfaces 33 and 34 forming the V-shaped groove or channel of the guide 7. Thus, said rear portion 37 forms a tongue which slidably engages in the channel 33, 34. The carriage 8 has a substantially thickened bottom portion 38 located beneath the surface 35 and between the forward end 36 and rear end 37. Said thickened portion 38 tapers downwardly and terminates in a downwardly and forwardly opening grooved bottom portion of a modified V-shaped cross section composed of the surfaces 39 and 40. When the tongue 37 is seated in the groove 33, 34, the downwardly facing surface 39 rests upon the top rail surface 30 and the forwardly facing surface 40 has a portion bearing against the upper part of the inner side 31 of the wall 29. Thus, the wall portions 30 and 31 form in effect a partial tongue on which the groove surfaces 39 and 40 slidably engage. The weight of the carriage 8 and parts supported thereby will maintain the carriage in its position as illustrated in Figure l on the guide 7 and said carriage will be prevented from rocking clockwise past its position of Figure 1 or from sliding either toward or away from the grinding wheel 9. However, said carriage will be free to slide longitudinally of the guide 7 and transversely of the sharpening wheel 9.

The carriage 8 also includes upstanding ribs which extend toward and away from the forward end 36 and rear end 37 and which form fences 41 which rise from and are disposed along the side edges of the top surface 35. The carriage 8 is provided with ears 42 which project outwardly from opposite sides thereof, substantially intermediate of the ends of the top surface 35. A threaded rod or stud 43 is fixed in and rises perpendicularly from each ear 42. A clamping bar 44 is disposed transversely over the surface 35 and the ribs or fences 41 and has openings 45 adjacent the ends thereof sized to loosely engage the upstanding studs 43. Wing nuts or the like 46 threadedly engage the studs 43 above the ends of the clamp 44.

Assuming that the mounting plate 6 is secured by the fastening 14 to the flange 11 and that the guide 7 is connected to the mounting plate 6 by the bolts 23 and 27 for sliding movement of the guide 7 on the plate 6 only in a direction transversely of said guide and toward and away from the sharpening wheel 9, the carriage 8 is placed on the guide 7 as illustrated in the drawing by inserting the tongue 37 into the groove 33, 34 by a simultaneous rearward and downward swinging movement of the carriage relatively to the guide. The nuts 46 are loosened so that the clamp 44 may be displaced upwardly away from the work supporting surface 35 and so that a blade 47 or the like may be inserted between the surface 35 and clamp 44 from the rear toward the forward end of the carriage and so as to position an end or edge 48 of the blade 47 in a position forwardly of the forward carriage end 36, as illustrated in Figures 1 and 2. The workpiece 47 has been illustrated as a plane blade or bit but it will be readily apparent that a chisel blade or other similar blade to be sharpened at one end may be mounted in the carriage. The blade or bit 47 is positioned with one side edge thereof in engagement with one of the ribs or fences 41 so that the forward edge 48 to be sharpened will be disposed straight across a portion of the sharpening wheel periphery 13, and the blade or hit 47 is then advanced toward the sharpening wheel 9 until its end 48 barely contacts a portion of the periphery 13. The nuts 46 are then tightened for clamping the blade or bit 47 between the clamp 44 and surface 35. The feed screw 27 is then revolved in a direction to advance it inwardly through the threaded bore 21 for moving the guide 7 and carriage 8 carried thereby toward the sharpening wheel 9. A one-half turn or revolution of the feed screw 27 will advance the guide and carriage a sufficient distance to properly position the cutting edge 48 relatively to the sharpening wheel periphery 13. The sharpening wheel 9 is then revolved and at the same time the carriage 8 is manually slid back and forth longitudi- .4 nally in the guide 7 to cause the edge 48 to travel back and forth across the sharpening wheel periphery 13. The carriage is thus moved slowly and longitudinally of the guide 7 until the bit portion 48 is no longer ground by the wheel periphery 13. The feed screw 27 is then turned another half turn in the same direction to again advance the guide 7, carriage 8 and blade or bit 47 toward the sharpening wheel 9, and the aforedescribed operation is then repeated.

Should the blade end 48 become hot during the sharpening operation, the operator merely swings the forward end 36 of the carriage 8 upwardly, causing the groove surfaces 39 and 40 to be swung out of engagement with the rail or track surfaces 30 and 31, respectively, and while the rear edge of the tongue 37 is sliding along the bottom surface 34 away from the groove surface 33 and at the same time fulcruming on said bottom surface 34, to disengage the carriage 8 from the guide 7, so that the carriage can be removed with the blade or hit 47. The blade or bit end 48 may then be dipped in water and after thus being cooled, the carriage 8 is re-applied to the guide 7 and the blade or bit end 48 will again be in a proper position to complete the grinding operation.

Where a chisel bit is being sharpened, a light pressure may be placed thereon near the sharpening wheel to balance the weight of the chisel handle, not shown, which will be disposed to the left of the attachment 5, as seen in Figures 1 and 2.

The attachment 5 will produce a slightly hollow ground edge which will be straight and at exactly a right angle to the longitudinal edge of the blade or hit which Is disposed in engagement with the inner edge of one of the fences 41.

No special skill is required to produce a perfectly ground cutting edge using the attachment 5. Furthermore, the periphery of the grinding wheel will never require dressing. With the use of the attachment 5, no high or low places will be left on the sharpened edge eliminating the need of subsequently employing an oil stone to smooth a ground edge.

Various modifications and changes are contemplated and may obviously be resorted to, without departing from the spirit or scope of the invention as hereinafter defined by the appended claims.

I claim as my invention:

1. A work holder of the character described comprising an elongated guide member, means detachably mounting the guide member crosswise of a grinding wheel in substantially a horizontal plane and normal to the plane of an adjacent portion of the grinding wheel periphery, said guide member having a rear portion disposed remote from the grinding wheel defining an upwardly and forwardly opening substantially V-shaped groove, said guide member having an upstanding front wall disposed adjacent the grinding wheel and parallel to the groove; a carriage demountably supported on the guide member for sliding movement longitudinally there of, said carriage having a rear portion of substantially wedge shaped cross section forming a tongue slidably engaging in said groove, said carriage having a bottom part spaced from said tongue including a portion slidably engaging on a top surface of said wall and an inclined forwardly facing portion slidably engaging against a portion of an inner surface of the wall and cooperating with said tongue and groove for slidably connecting the carriage to the guide member, and clamping means forming a part of the carriage and adapted to clamp a blade or hit in the carriage at an incline relative to the plane of the guide member for positioning an edge of the blade or bit in engagement on the grinding wheel periphery at a point circumferentially spaced from the peripheral portion of the grinding wheel located adjacent said guide member.

2. A work holder as in claim 1, said carriage including a forward portion, said bottom part of the carriage 5 6 being disposed between and spaced from said forward 447,015 Reiss Feb. 24, 1891 portion and tongue, and said carriage being substan 553,828 Blood Feb. 4, 1896 tially thicker adjacent said bottom part than adjacent 557,301 Blumenfeld Mar. 31, 1896 said tongue whereby the carriage is gravity urged down- 981,810 Sterling Jan. 17, 1911 wardly into engagement with said front wall. 5 1,275,208 Bockshe Aug. 13, 1918 1,880,673 Bath Oct. 4, 1932 References Cited in the file of this patent 2,052,837 Makaroif Sept. 1, 1936 N ED P 4204 H ZIe STATES A'IENTSSe t 23 1845 FOREIGN PATENTS 3501351 Dammit-5571111111111- 3a. 5: 1886 10 330,352 Great Britain 1m 9, 1930 354,690 Cleary Dec. 21, 1886 884,788 France May 1943 

